Thyroid hormones and changes in body weight and metabolic parameters in response to weight loss diets: the POUNDS LOST trial

The Impact of Thyroid Hormones on Cardiometabolic Risk in Children and Adolescents with Obesity, Overweight and Normal Body Mass Index (BMI): A One-Year Intervention Study

Thyroid hormones regulate metabolism and have a major impact in maintaining cardiovascular homeostasis. The purpose of our study was to examine the relation of thyrotropin (TSH) and thyroid hormones with cardiometabolic parameters in children and adolescents with obesity, overweight, and normal body mass index (BMI) before and after the implementation of a comprehensive, multidisciplinary, personalized, lifestyle intervention program for 1 year. One thousand three hundred and eleven (n = 1311) children and adolescents aged 2 to 18 years (mean age ± SD: 10.10 ± 2.92 years) were studied prospectively. Patients were categorized as having obesity (n = 727, 55.45%), overweight (n = 384, 29.29%) or normal BMI (n = 200, 15.26%) according to the International Obesity Task Force (IOTF) cutoff points. All patients received personalized guidance on diet, sleep, and physical activity at regular intervals throughout the 1-year period. Detailed clinical evaluation and hematologic, biochemical and endocrinologic investigations were performed at the beginning and the end of the study. Subjects with obesity had a more adverse cardiometabolic risk profile than subjects with overweight and normal BMI on both assessments. At initial evaluation, total T3 concentrations were positively associated with uric acid and HbA1C, and free T4 concentrations were negatively associated with insulin concentrations, while there was no association between TSH concentrations and cardiometabolic risk parameters. Following the 1 year of the multidisciplinary, lifestyle intervention program, the concentrations of lipids, HbA1C, ALT, and γGT improved significantly in all subjects. Changes in TSH concentrations were positively associated with changes in systolic blood pressure (SBP), glucose, triglycerides, and cholesterol concentrations. Changes in free T4 concentrations were negatively associated with changes in cholesterol and insulin concentrations. Furthermore, changes in T3 concentrations were positively associated with changes in HbA1C, glucose, uric acid, and triglyceride concentrations. These findings indicate that in children and adolescents with overweight and obesity, thyroid hormones are associated with indices conferring cardiometabolic risk.

Impact of peripheral thyroid hormone balance on liver fat: insights from the NutriAct trial

OBJECTIVE

Hypothyroidism has been proposed as a potential contributor to steatotic liver disease (SLD), but existing data shows conflicting results in euthyroid subjects. Therefore, we investigated the association between thyroid function and intrahepatic lipids (IHLs) during a 36-month randomized controlled trial evaluating a diet known to reduce liver fat.

DESIGN

502 eligible subjects (aged 50-80 years, ≥1 risk factor for unhealthy aging) were randomly assigned to either follow a diet rich in unsaturated fatty acids, plant protein, and fiber (intervention group, IG), or dietary recommendations of the German Nutrition Society (control group, CG).

METHODS

Serum levels of thyroid hormones (THs) as well as IHLs, defined via magnetic resonance spectroscopy, were measured within an euthyroid subgroup without significant alcohol consumption at baseline (n = 332) and after 12 months (n = 243). A ratio of T3/T4 was used to assess whole-body deiodinase activity. Estimates of glucose and lipid metabolism were analyzed.

RESULTS

Only fT3 and T3/T4 ratios showed a significant positive correlation with IHL at baseline. We observed a significant decline in fT3, T3, fT3/fT4 ratio, and T3/T4 ratio in CG and IG after 12 months without significant differences between groups. TSH, fT4, and T4 remained stable. A larger improvement of IHL during dietary intervention was seen in those subjects with a lower decline in T3 concentrations.

CONCLUSIONS

Altered TH balance indicates a possible compensatory upregulation of whole-body TH activity in subjects with increased liver fat. This might be also relevant during the improvement of hepatic steatosis.

Is There an Ideal Diet? Some Insights from the POUNDS Lost Study

Diets for weight loss have a long history but an ideal one has not yet been clearly identified. To compare low-fat and lower carbohydrate diets, we designed The Preventing Overweight by Novel Dietary Strategies (POUNDS) Lost study. This is a 2 × 2 factorial study with diets of 20% or 40% fat and 15% or 25% protein with a graded carbohydrate intake of 35, 45, 55 and 65%. Weight loss, overall, was modest at nearly 6% with all four diets, and no significant dietary difference. The variability in weight loss in each diet group was significant, ranging from greater than 20% to a small weight gain. Studies of genetic variations in relation to weight loss showed that the diet that was selected could significantly affect weight loss, emphasizing that there is no ideal diet and more than one diet can be used to treat obesity. Weight loss was also influenced by the level of baseline triiodothyronine or thyroxine, and baseline carbohydrate and insulin resistance. Achieving a stable Health Eating Food Diversity Index, eating more protein, eating more fiber, engaging in more physical activity, sleeping better and eating less ultra-processed foods were beneficial strategies for weight loss in this trial. Although there is no "ideal diet", both the DASH diet and the Mediterranean diet have clinical trials showing their significant benefit for cardiovascular risk factors. Finally, the lesson of the "Last Chance Diet", which recommended a diet with protein from gelatin, proved that some diets could be hazardous.

SGLT2 inhibitor as a potential therapeutic approach in hyperthyroidism-induced cardiopulmonary injury in rats

Hyperthyroidism-induced cardiac disease is an evolving health, economic, and social problem affecting well-being. Sodium-glucose cotransporter protein 2 inhibitors (SGLT2-I) have been proven to be cardio-protective when administered in cases of heart failure. This study intended to investigate the potential therapeutic effect of SGLT2-I on hyperthyroidism-related cardiopulmonary injury, targeting the possible underlying mechanisms. The impact of the SGLT2-I, dapagliflozin (DAPA), (1 mg/kg/day, p.o) on LT4 (0.3 mg/kg/day, i.p)-induced cardiopulmonary injury was investigated in rats. The body weight, ECG, and serum hormones were evaluated. Also, redox balance, DNA fragmentation, inflammatory cytokines, and PCR quantification in heart and lung tissues were employed to investigate the effect of DAPA in experimentally induced hyperthyroid rats along with histological and immunohistochemical examination. Coadministration of DAPA with LT4 effectively restored all serum biomarkers to nearly average levels, improved ECG findings, and reinstated the redox balance. Also, DAPA could improve DNA fragmentation, elevate mtTFA, and lessen TNF-α and IGF-1 gene expression in both organs of treated animals. Furthermore, DAPA markedly improved the necro-inflammatory and fibrotic cardiopulmonary histological alterations and reduced the tissue immunohistochemical expression of TNF-α and caspase-3. Although further clinical and deep molecular studies are required before transposing to humans, our study emphasized DAPA's potential to relieve hyperthyroidism-induced cardiopulmonary injury in rats through its antioxidant, anti-inflammatory, and anti-apoptotic effects, as well as via antagonizing the sympathetic over activity.

Correlation Between Impaired Sensitivity to Thyroid Hormones and Serum Uric Acid in Female Patients With Obesity and After Laparoscopic Sleeve Gastrectomy

OBJECTIVE

An alterable risk factor for hyperuricemia is obesity. Additionally, obese people may have a moderate form of acquired resistance to thyroid hormones. Thyrotropin, thyroid hormones, and obesity all interact subtly. However, the connection between thyroid hormone sensitivity and hyperuricemia in obese patients both before and after laparoscopic sleeve gastrectomy (LSG) has not yet been clarified. The objective of our study was to investigate the connection between impaired thyroid hormone sensitivity and elevated uric acid (UA) levels before and after LSG.

METHODS

In total, 1054 euthyroid patients with obesity (481 males, 573 females), 248 (143 female patients) of whom underwent subsequent LSG, were enrolled in this retrospective study. Anthropometric measurements and thyroid hormone and UA levels were taken before and 3 months after LSG.

RESULTS

Female patients with obesity with impaired sensitivity to thyroid hormones had higher UA levels (P for trend <.01). The odds ratio of the fourth vs first quartile of thyroid feedback quantile index, thyrotropin index, and thyrotropin-thyroxine resistance index were 4.285 (confidence interval: 1.360-13.507), 3.700 (confidence interval: 1.276-10.729), and 2.839 (confidence interval: 1.014-7.948), respectively, with robust relationships with female hyperuricemia (all P < .05). However, there was only a positive correlation between the decline in UA levels and thyroid feedback quantile index, thyrotropin, and thyrotropin-thyroxine resistance index in female patients following LSG.

CONCLUSION

Female hyperuricemia is correlated with higher thyroid hormone resistance index scores. Resistance to thyroid hormones was greatly improved by LSG. The decrease in UA levels after surgery is correlated with the improvement of thyroid hormone resistance after LSG.

Basal metabolic rate and the risk of urolithiasis: a two-sample Mendelian randomization study

OBJECTIVE

Few studies have investigated the impact of basal metabolic rate (BMR) on the development of urolithiasis, and the causal relationship is yet to be established. In this study, a two-sample Mendelian randomization (MR) analysis was utilized to identify the causal relationship between BMR and risk of urolithiasis.

METHOD

Genetic instruments for BMR were drawn from a public genome-wide association study (GWAS). Summary dates on BMR and urolithiasis were obtained from a GWAS meta-analysis with sample sizes of 454,874 and 212,453, respectively. The inverse-variance weighted (IVW) method was provided as the main approach to estimate the causal relationship. The weighted-median method and the MR-Egger method were used as supplements to the IVW method. In addition, we conducted sensitivity analyses, including heterogeneity tests, pleiotropy tests and leave-one-out analysis, to assess the robustness of the outcomes. Furthermore, the funnel plot asymmetry was visually inspected to evaluate possible bias.

RESULTS

The inverse-variance weighted data revealed that genetically predicted BMR significantly decreased the risk of urolithiasis [beta coefficient (beta): - 0.2366, odds ratio (OR): 0.7893, 95% confidence interval (CI) 0.6504-0.9579, p = 0.0166].

CONCLUSIONS

BMR has causal effects on urolithiasis in an MR study, and the risk of urolithiasis in patients with lower levels of BMR is higher.

Effect of Ramadan fasting on thyroid functions in hypothyroid patients taking levothyroxine: a systematic review and meta-analysis

BACKGROUND

The major changes in the timing of meals during Ramadan may be challenging for hypothyroid patients on levothyroxine. We aimed to study the effect of Ramadan fasting on thyroid functions in hypothyroid patients taking levothyroxine.

METHODS

We did a comprehensive search of 8 databases for Randomized controlled studies (RCTs) and observational studies investigating the effect of Ramadan fasting on thyroid functions in hypothyroid individuals taking levothyroxine. Relevant data was extracted and analyzed. Mean difference (MD) and standard deviation (SD) were used to evaluate the continuous data. Risk ratios (RR) with a 95% confidence interval were used for outcomes constituting dichotomous data. National Institutes of Health (NIH) tools were used to assess the risk of bias.

RESULTS

Fourteen studies met our inclusion criteria, 3 RCTs, and 11 observational studies, all designed as pre-post studies. Ramadan fasting was associated with a statistically significant increase in TSH in patients who were euthyroid before Ramadan (MD = -0.76 [95% CI; -1.27, -0.25]). However, free thyroxine (FT4) was found to be stable (MD = 0.01, [95% CI; -0.03, 0.06]). All timing points were associated with a significant increase in TSH levels after Ramadan, pre-iftar (MD = -0.69 [95% CI; -1.03, -0.36]), post-iftar (MD = -0.76 [95% CI; -1.12, -0.39]), and pre-suhoor (MD = -1.19 [95% CI; -2.18, -0.19]).

CONCLUSION

TSH increases significantly after Ramadan. No timing point has superiority in maintaining thyroid control. However, choosing the timing should be individualized according to the patient's preference to guarantee the most possible compliance.

Comparison of Sodium Selenite and Selenium-Enriched Spirulina Supplementation Effects After Selenium Deficiency on Growth, Tissue Selenium Concentrations, Antioxidant Activities, and Selenoprotein Expression in Rats

Selenium contributes to physiological functions through its incorporation into selenoproteins. It is involved in oxidative stress defense. A selenium deficiency results in the onset or aggravation of pathologies. Following a deficiency, the repletion of selenium leads to a selenoprotein expression hierarchy misunderstood. Moreover, spirulina, a microalga, exhibits antioxidant properties and can be enriched in selenium.. Our objective was to determine the effects of a sodium selenite or selenium-enriched spirulina supplementation. Thirty-two female Wistar rats were fed for 12 weeks with a selenium-deficient diet. After 8 weeks, rats were divided into 4 groups and were fed with water, sodium selenite (20 μg Se/kg body weight), spirulina (3 g/kg bw), or selenium-enriched spirulina (20 μg Se/kg bw + 3 g spirulina/kg bw). Another group of 8 rats was fed with normal diet during 12 weeks. Selenium concentration and antioxidant enzyme activities were measured in plasma, urine, liver, brain, kidney, heart, and soleus. Expression of GPx (1, 3), Sel (P, S, T, W), SEPHS2, TrxR1, ApoER2, and megalin were quantified in liver, kidney, brain, and heart. We showed that a selenium deficiency leads to a growth delay, reversed by selenium supplementation despite a minor loss of weight in week 12 for SS rats. All tissues displayed a decrease in selenium concentration following deficiency. The brain seemed protected. We demonstrated a hierarchy in selenium distribution and selenoprotein expression. A supplementation of sodium selenite improved GPx activities and selenoprotein expression while a selenium-enriched spirulina was more effective to restore selenium concentration especially in the liver, kidney, and soleus.

Thyroid hormone levels and BMI-SDS changes in adolescents with obesity

Background

Thyroid hormones play an important role in energy metabolism and weight control, explained mostly by inducing thermogenesis and increasing basal metabolic rate. It has recently been shown that FT4 levels are associated with food preferences, which might also play a role in modulating body weight. The aim of this longitudinal follow-up study was to analyze the relationship of thyroid hormones levels (FT4, TSH) at baseline with weight/BMI-SDS changes in children and adolescents with obesity.

Methods

Three hundred seventy-seven children and adolescents have been enrolled to this study and followed up without a systematic intervention program for 5.59 ± 1.85months. Children and adolescents were divided into three subgroups: 1) 144 adolescents with obesity (15-19 years), 2) 213 children with obesity (10-14.9 years), and 3) 20 lean adolescents (15-19 years). Thyroid hormones were measured at the baseline, and anthropometry was performed at the baseline and during the follow-up. For further analyses, participants were divided according to the BMI-SDS change into two groups: 1. with BMI-SDS decrease, and 2. with BMI-SDS increase.

Results

Adolescents with obesity from the BMI-SDS decrease group had significantly lower baseline serum levels of TSH compared to the BMI-SDS increase group (2.4 ± 1.0 vs. 3.2 ± 2.0mIU/l; p=0.005). Similar difference was found for FT4 levels (14.7 ± 2.2 in the BMI-SDS decrease group vs. 15.5 ± 2.7pmol/l in the BMI-SDS increase group, p=0.048). Moreover, the BMI-SDS decrease was present in significantly higher percentage of adolescents with obesity with lower than median TSH level compared to those with higher than median TSH level at baseline (61.1% vs 38.6%, p=0.011). Likewise, the BMI-SDS decrease was present in significantly higher percentage of adolescent females with obesity and lower than median FT4 compared to those with higher than median FT4 level at baseline (70.6% vs. 23.5%, p<0.001). No associations of baseline thyroid hormones with the BMI-SDS change were observed in children with obesity or lean adolescents.

Conclusion

Adolescents with obesity and increased BMI-SDS during the follow-up had significantly higher baseline levels of both TSH and FT4 compared to BMI-SDS decrease group. These results support the previous findings that higher FT4 in individuals with obesity may influence weight gain.

The Effects of the Paleo Diet on Autoimmune Thyroid Disease: A Mixed Methods Review

The aim of this systematic review was to examine the characteristics of Paleolithic diet (PD) interventions designed for adult patients with autoimmune thyroid disease (AITD) in order to determine if diet elements have the potential to successfully reduce thyroid antibodies (Ab) such as thyroglobulin (Tg), thyroid peroxidase (TPO), and thyroid stimulating hormone receptor (TSHR), and improve thyroid hormones (thyroxine (T4), triiodothyronine (T3) and thyroid stimulating hormone (TSH)) or resolve AITD pathogenesis. Randomized controlled trials (RCTs) with an adult population of 18 years and older, diagnosed with Hashimoto's thyroiditis (HT) or Graves' disease (GD) (Basedow's), who were placed on a diet of Paleolithic or ancestral nature, and achieved reduction of AITD Abs, improvement of thyroid hormones, and, or resolution of AITD were searched. Various electronic databases were used. Bias was assessed using critical appraisal tools from the Scottish Intercollegiate Guidelines Network (SIGN) and Joanna Briggs Institute (JBI). Studies were excluded according to exclusion criteria and results analyzed. One randomized controlled trial (RCT), a pilot study, and six case studies were found. In total, eight AITD studies focusing on Paleolithic or ancestral interventions were located. In highlight, females were the predominant gender. Case studies solely focused on AITD with protocols ranging from 8-60 weeks. All studies showed clinical improvements, one had significant improvement, two showed AITD resolution. After structured evaluation of nutritional interventions utilizing the PD on the effects of AITD, it was concluded foods of ancestral nature along with the addition of specific supplements, food components, exercise and mindfulness meditation, and exclusion of modern day foods have a considerable impact on thyroid Ab and hormones. The relevant studies suggest while this dietary protocol can be useful in clinical practice, larger-scale studies need to be conducted. Key teaching pointsThere are currently no dietary interventions recommended for the treatment of autoimmune thyroid disease. The Paleo diet has been documented to improve AITD antibodies and thyroid hormones in both Hashimoto's thyroiditis and Graves' disease.The Paleo diet can provide a natural source of nutrients similar to supplemental nutrients that have shown positive results on AITD.The paleo diet provides specific macronutrient percentages that may be beneficial in reducing AITD antibodies, while improving thyroid hormones.Methylation supplementation may be useful in AITD cases.

Keto Menu-Effect of Ketogenic Menu and Intermittent Fasting on the Biochemical Markers and Body Composition in a Physically Active Man-A Controlled Case Study

The combination of ketogenic diet (KD) with intermittent fasting (IF) has, for years, aroused a great interest in the scientific world and among healthy lifestyle enthusiasts. Its importance is even greater when the study subjects are physically active individuals. The aim of the study was a determination of the effect of strict calculated ketogenic menu combined with IF and with caloric deficit on the selected biochemical markers and body composition in a 23-year-old man performing strength training. At the same time, we decided to conduct the first so-deeply investigated and controlled case study in this respect. The study protocol included a 13-week-long ketogenic diet with intermittent fasting (of delayed time-restricted eating 16:8 type) and caloric deficit. A detailed menu was designed and was used by the man throughout the whole study duration. A number of blood tests were performed before and after the implemented dietary intervention. Additionally, body composition was determined weekly and the concentrations of glucose and ketone bodies, as well as pulse rate and arterial pressure, were measured daily. The most important changes noted included a significant increase in testosterone and vitamin D concentrations and significant reduction in the HOMA-IR index and concentrations of hepatic enzymes, insulin, glucose, iron, urea, and free triiodothyronine (FT3). Moreover, a significant improvement of body composition occurred (the ratio of total body mass to the adipose and muscular tissue and water mass improved). Favourable changes were also noted in heart rate and arterial pressure values. In view of that, the KD with IF and caloric deficit exerted favourable effects on most biochemical parameters and on body composition and caused an almost twofold increase in serum testosterone concentration.

Toward Precision Weight-Loss Dietary Interventions: Findings from the POUNDS Lost Trial

The POUNDS Lost trial is a 2-year clinical trial testing the effects of dietary interventions on weight loss. This study included 811 adults with overweight or obesity who were randomized to one of four diets that contained either 15% or 25% protein and 20% or 40% fat in a 2 × 2 factorial design. By 2 years, participants on average lost from 2.9 to 3.6 kg in body weight in the four intervention arms, while no significant difference was observed across the intervention arms. In POUNDS Lost, we performed a series of ancillary studies to detect intrinsic factors particular to genomic, epigenomic, and metabolomic markers that may modulate changes in weight and other cardiometabolic traits in response to the weight-loss dietary interventions. Genomic variants identified from genome-wide association studies (GWASs) on obesity, type 2 diabetes, glucose and lipid metabolisms, gut microbiome, and dietary intakes have been found to interact with dietary macronutrients (fat, protein, and carbohydrates) in relation to weight loss and changes of body composition and cardiometabolic traits. In addition, we recently investigated epigenomic modifications, particularly blood DNA methylation and circulating microRNAs (miRNAs). We reported DNA methylation levels at NFATC2IP, CPT1A, TXNIP, and LINC00319 were related to weight loss or changes of glucose, lipids, and blood pressure; we also reported thrifty miRNA expression as a significant epigenomic marker related to changes in insulin sensitivity and adiposity. Our studies have also highlighted the importance of temporal changes in novel metabolomic signatures for gut microbiota, bile acids, and amino acids as predictors for achievement of successful weight loss outcomes. Moreover, our studies indicate that biochemical, behavioral, and psychosocial factors such as physical activity, sleep disturbance, and appetite may also modulate metabolic changes during dietary interventions. This review summarized our major findings in the POUNDS Lost trial, which provided preliminary evidence supporting the development of precision diet interventions for obesity management.

Metabolism disturbance by light/dark cycle switching depends on the rat health status: the role of grape seed flavanols

Changes in light/dark cycles and obesogenic diets are related to the disruption of circadian rhythms and metabolic disorders. Grape seed flavanols have shown beneficial effects on metabolic diseases and, recently, a circadian system modulation has been suggested to mediate their health-enhancing properties. Therefore, the aim of this study was to evaluate the grape seed (poly)phenol extract (GSPE) effects in healthy and obese rats after a light/dark cycle disruption. Forty-eight rats were fed a standard (STD) or cafeteria (CAF) diet for 6 weeks under STD conditions of a light/dark cycle (12 h light per day, L12). Then, animals were switched to a long (18 h light per day, L18) or short (6 h light per day, L6) photoperiod and administered a vehicle (VH) or GSPE (25 mg kg-1) for 1 week. The results showed changes in serum lipids and insulin and metabolomic profiles dependent on the photoperiod and animal health status. GSPE administration improved serum parameters and increased the Nampt gene expression in CAF rats and modified the metabolomic profile in a photoperiod-dependent manner. Metabolic effects of light/dark disturbance depend on the health status of the rats, with diet-induced CAF-induced obese rats being more affected. Grape seed flavanols improve the metabolic status in a photoperiod-dependent manner and their effects on the circadian system suggest that part of their metabolic effects could be mediated by their action on biological rhythms.

Appetite, Energy Expenditure, and the Regulation of Energy Balance

At usual weight, energy intake and expenditure are coupled and covary to maintain body weight (energy stores). A change in energy balance, especially weight loss, invokes discoordinated effects on energy intake and output that favor return to previous weight. These regulatory systems reflect physiological changes in systems regulating energy intake and expenditure rather than a lack of resolve. The biological and behavioral physiology of dynamic weight change are distinct from those of attempts at static weight maintenance of an altered body weight. This suggests that optimal therapeutic approaches to losing or gaining vs. sustaining weight changes are different for most individuals.

Prevalence and clinical profile of abnormal glucose in first-episode and drug-naïve patients with major depressive disorder with comorbid abnormal thyroid function: a large-scale cross-sectional study

BACKGROUND

The associated factors of abnormal glucose in patients with major depressive disorder (MDD) with comorbid abnormal thyroid function (ATF) remain unclear. To the best of our knowledge, this is the first study with a large sample size that examines the risk factors of abnormal glucose in first-episode drug-naïve (FEDN) MDD patients comorbid with ATF and includes clinical correlates and thyroid hormone levels.

METHODS

A total of 1718 FEDN MDD patients were recruited. The Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), and Positive and Negative Syndrome Scale (PANSS) positive subscale were used to evaluate the symptoms of patients. Fasting blood glucose concentration and thyroid hormone levels were measured.

RESULTS

The prevalence of abnormal glucose in MDD patients with comorbid ATF was 47.3%, which was 4.25 times higher than that in MDD patients without ATF (17.4%). Compared to those ATF patients without abnormal glucose, ATF patients with abnormal glucose scored higher on HAMD, HAMA and PANSS positive subscale, had a higher rate of suicide attempts, severe anxiety and psychotic symptoms, and had higher levels of thyroid-stimulating hormone (TSH), and thyroid peroxidases antibody (TPOAb) which were also correlated with abnormal glucose in MDD patients comorbid ATF (all P < 0.05). The combination of HAMD score and TSH could differentiate abnormal glucose from ATF. Further, TSH was independence-related with the concentration of fasting blood glucose in MDD patients with comorbid ATF.

CONCLUSION

Our results demonstrate a high prevalence of abnormal glucose in MDD patients with comorbid ATF. Some clinical and thyroid function-related variables may be associated with abnormal glucose in MDD patients with comorbid ATF.

Effectiveness of Bariatric Surgery for Improving Thyroid Function and Reducing Levothyroxine Dose in Patients With Obesity and Overt Hypothyroidism

BACKGROUND

 Hypothyroidism is a major hormonal condition that affects more women than men in Saudi Arabia. Studies indicate a bidirectional link between hypothyroidism and obesity, which may improve following bariatric surgery (BS). The focus of this research is to assess how hypothyroidism patients' thyroid function and levothyroxine dosage are impacted by bariatric surgery.

METHODOLOGY

This was an observational retrospective study conducted in two centres at Taif, Saudi Arabia. All morbidly obese patients who were diagnosed with overt hypothyroidism and underwent laparoscopic sleeve gastrectomy from January 2016 to December 2021 were included. The changes in the thyroid profile and the changes in the doses or cessation of levothyroxine were evaluated after the laparoscopic sleeve gastrectomy.

RESULTS

Our results demonstrate that a total of 70 patients dominated by women out of 1202 from both centers who meet our inclusion criteria showed a statistically significant decrease on comparison of clinical parameters (thyroid-stimulating hormone [TSH], free T4 [FT4], free T3 [FT3], levothyroxine [L-T4]) before and after BS. The average TSH levels were determined to be 4.45 ± 4.41 mIU/L prior to BS, and they significantly decreased (3.17 ± 2.77 mIU/L) following BS (p=0.009). When compared to before BS (13.17 ± 2.73 pmol/L), the mean FT4 levels after BS (11.63 ± 5.88 pmol/L) exhibited a significant decline (p=0.046). The mean FT3 levels before and after BS also were statistically significantly lower (1.94 ± 2.12 pg/mL) than before (2.75 ± 1.96 pg/mL), p=0.009. The mean L-T4 levels after BS considerably decreased from before BS (98.68 ± 56.18 mcg) to after BS (79.39 ± 41.49 mcg), p=0.046.

CONCLUSION

Better thyroid profiles and lower levothyroxine dosage show that bariatric surgery improves hypothyroidism.

Lactation duration and lifetime progression to metabolic syndrome in women according to their history of gestational diabetes: a prospective longitudinal community-based cohort study

BACKGROUND

Despite the many signs of progress in pharmacotherapies, metabolic syndrome (MetS) is one of the main public-health burdens worldwide. Our study aimed to compare the effect of breastfeeding (BF) in women with and without gestational diabetes mellitus (GDM) on MetS incidence.

METHODS

Of females who participated in the Tehran Lipid and glucose study, women who met our inclusion criteria were selected. The Cox proportional hazards regression model, with adjustment of potential confounders, was done to evaluate the relationship between duration of BF and incident of MetS in women with a GDM history compared to non-GDM.

RESULTS

Out of 1176 women, there were 1001 non-GDM and 175 GDM. The median follow-up was 16.3 (11.9, 19.3) years. Results of the adjusted model illustrated that the total BF duration was negatively associated with MetS incidence risk (hazard ratio (HR) 0.98, 95% CI 0.98-0.99) in total participants indicating that per one-month increase of BF duration, the hazard of MetS reduced by 2%. The HR of MetS in Comparison between GDM and non-GDM women demonstrated significantly more reduced MetS incidence with a longer duration of exclusive BF (HR 0.93, 95% CI 0.88-0.98).

CONCLUSIONS

Our findings illustrated the protective effect of BF, especially exclusive BF, on MetS incidence risk. BF is more effective in reducing the risk of MetS among women with a history of GDM than among women without such a history.

Thyroid axis hormones and anthropometric recovery of children/adolescents with overweight/obesity: A scoping review

Introduction

Thyroid hormones exert multiple physiological effects essential to the maintenance of basal metabolic rate (BMR), adaptive thermogenesis, fat metabolism, growth, and appetite. The links between obesity and the hormones of the thyroid axis, i.e., triiodothyronine (T3), thyroxine (T4), and thyrotropin (TSH), are still controversial, especially when considering children and adolescents. This population has high rates of overweight and obesity and several treatment approaches, including nutritional, psychological, and physical exercise interventions have been used. Understanding the importance of the hormones of the thyroid axis in the recovery from overweight and obesity may help directing measures to the maintenance of a healthy body composition. The present scoping review was carried out to analyze studies evaluating these hormonal levels throughout interventions directed at treating overweight and obesity in children and adolescents. The main purpose was to ascertain whether the hormones levels vary during weight loss.

Methods

We selected for analysis 19 studies published between 1999 and 2022.

Results

Most of the studies showed that changes in different anthropometric indicators, in response to the multidisciplinary interventions, correlated positively with free T3 (fT3), total T3 (TT3), and TSH. With respect to free T4 (fT4) and total T4 (TT4).

Discussion

The most common finding was of unchanged levels and, hence, no significant association with weight loss. Moreover, thyroxine supplementation has failed to affect the response to the interventions. Further studies are necessary to elucidate the relevance of the variations in hormone levels to the establishment of overweight/obesity and to the recovery from these conditions in children/adolescents.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42020203359.

Body composition changes following total thyroidectomy: A one-year follow-up study

INTRODUCTION

Thyroid hormones play an important role in body weight regulation. In this study, we investigated which body composition parameters cause a change in body weight after total thyroidectomy.

MATERIALS AND METHOD

We performed a retrospective cohort study of a prospectively maintained database of patients who underwent total thyroidectomy. Demographics, thyroid function tests, indications for surgery, final pathology, and postoperative thyroid status were collected. Body composition analyses measured by the bioelectrical impedance analysis method were recorded at two-time points, 12 months apart.

RESULTS

Forty-four patients were included in the study with a mean age of 51.6 years. There were statistically significant increases in weight (p=0.049), body mass index (p=0.021), and fat mass (p=0.001) over time. While 12 patients (27.3%) lost or maintained weight, 32 patients (72.7%) gained weight. There was no significant difference in age, sex, preoperative thyroid function tests, postoperative thyroid status, or pathology between those who gained weight and those who did not. Although changes in all body composition parameters were higher in males than in females, these differences were not significant overall. Multivariable regression analysis revealed a significant positive relationship between increase in fat mass and baseline free-T₃ (p=0.041) and found that lower baseline percent body fat was a significant factor for greater fat mass gain (p=0.016). However, no predictors of change in weight were identified.

CONCLUSION

We conclude that total thyroidectomy results in a significant change in body weight and fat mass. Higher free-T₃ and lower percent body fat at baseline were significant factors of fat mass gain.

Late offspring effects of antenatal thyroid screening

BACKGROUND

Thyroid dysfunction in pregnancy is associated with adverse offspring outcomes and recent birth-cohort studies suggest that even mild degrees of thyroid dysfunction may be linked with a range of late cognitive and behavioural effects in childhood and adolescence.

SOURCES OF DATA

This review summarizes recent literature of observational studies and critically appraises randomized controlled trials (RCTs) of antenatal thyroid screening and Levothyroxine intervention.

AREAS OF AGREEMENT

Overt hypothyroidism and hyperthyroidism carry significant risks for unfavourable offspring outcomes and should be appropriately corrected in pregnancy.

AREAS OF CONTROVERSY

The significance of subclinical hypothyroidism and hypothyroxinaemia is still unclear. Meta-analyses of birth-cohort studies show associations of maternal subclinical hypothyroidism and hypothyroxinaemia with intellectual deficits, attention deficit hyperactivity disorder (ADHD) and autism spectrum disorders, while hyperthyroidism and high-normal FT4 were linked with ADHD. RCTs have shown no benefits of screening on neurodevelopmental outcomes although Levothyroxine could have been initiated too late in pregnancy in these trials.

GROWING POINTS

A small number of studies have shown inconsistent associations of maternal thyroid dysfunction with offspring cardiometabolic indices including blood pressure and body weight. Correction of maternal thyroid dysfunction was, however, associated with favourable long-term metabolic profiles in mothers, including lipid profiles, fat mass and body mass index. Antenatal thyroid screening may therefore present opportunities for optimizing a wider range of outcomes than envisaged.

AREAS FOR DEVELOPING RESEARCH

Future trials with early antenatal thyroid screening and intervention are necessary to clarify the impact of screening on late offspring and maternal effects.

The Effects of Zinc and Selenium Supplementation on Body Composition and Thyroid Function in Individuals with Overweight or Obesity: A Systematic Review

People with obesity have been found to have lower zinc (Zn) and selenium (Se) circulatory levels and abnormal thyroid function than people with normal weight. Studies about the effects of Zn and Se supplementation on body composition and thyroid function of overweight-obese people showed inconsistent results. A systematic review of randomized controlled trials was conducted to determine the effects of Ζn supplementation, Se supplementation, and their combination on body composition and thyroid function of individuals with overweight or obesity. Databases of PubMed, ScienceDirect, and Cochrane, were searched from inception to February 27, 2022, to identify relevant articles. For the assessment of the methodological quality of the studies, the Jadad scale was used. After screening the articles, thirteen studies were finally included and were analyzed using the strength of the evidence approach. Regarding the effectiveness of Zn supplementation on body composition, moderate evidence was found, while the effects of Se were found to be mixed. Zn supplementation was found to affect the thyroid function of people with overweight or obesity by increasing their free triiodothyronine (FT3) levels. However, this result is based only on one study among hypothyroid patients. At this point, the effectiveness of Zn, Se, and their combination, on the body composition and the thyroid function of people with overweight or obesity cannot safely be determined because of the controversial results, small number, and the limitations of the identified studies. The results of this systematic review must be interpreted with caution due to the limitations detected.

Beyond appetite regulation: Targeting energy expenditure, fat oxidation, and lean mass preservation for sustainable weight loss

New appetite-regulating antiobesity treatments such as semaglutide and agents under investigation such as tirzepatide show promise in achieving weight loss of 15% or more. Energy expenditure, fat oxidation, and lean mass preservation are important determinants of weight loss and weight-loss maintenance beyond appetite regulation. This review discusses prior failures in clinical development of weight-loss drugs targeting energy expenditure and explores novel strategies for targeting energy expenditure: mitochondrial proton leak, uncoupling, dynamics, and biogenesis; futile calcium and substrate cycling; leptin for weight maintenance; increased sympathetic nervous system activity; and browning of white fat. Relevant targets for preserving lean mass are also reviewed: growth hormone, activin type II receptor inhibition, and urocortin 2 and 3. We endorse moderate modulation of energy expenditure and preservation of lean mass in combination with efficient appetite reduction as a means of obtaining a significant, safe, and long-lasting weight loss. Furthermore, we suggest that the regulatory guidelines should be revisited to focus more on the quality of weight loss and its maintenance rather than the absolute weight loss. Commitment to this research focus both from a scientific and from a regulatory point of view could signal the beginning of the next era in obesity therapies.

Thyroid Function Alteration in Obesity and the Effect of Bariatric Surgery

The most common endocrine disease in obesity is hypothyroidism and secondary endocrine alterations, including abnormal thyroid function, are frequent in obesity. It is unclear whether impaired thyroid function is the cause or the consequence of increased adiposity; furthermore, there are no clear data regarding the best way to dose levothyroxine for patients with both hypothyroidism and obesity, and the effect of bariatric surgery (BS). The aim of the present article is to review some controversial aspects of the relation between obesity and the thyroid: (1) Thyroid function in obesity and the effect of BS (2) Thyroid hormone treatment (THT) in obese patients with hypothyroidism and the effect of BS. In summary: In morbidly obese patients, TSH is moderately increased. Morbid obesity has a mild central resistance to the thyroid hormone, reversible with weight loss. In morbidly obese hypothyroid patients, following weight loss, the levothyroxine dose/kg of ideal weight did not change, albeit there was an increment in the levothyroxine dose/kg of actual weight. From a clinical practice perspective, in morbid obesity, diagnosing mild hypothyroidism is difficult, BS improves the altered thyroid function and THT can be adapted better if it is based on ideal weight.

Inflammasome activation as a link between obesity and thyroid disorders: Implications for an integrated clinical management

Obesity is strongly associated with chronic low-grade inflammation. Obese patients have an increased risk to develop thyroid autoimmunity and to became hypothyroid, suggesting a pathogenetic link between obesity, inflammation and autoimmunity. Moreover, type 2 diabetes and dyslipidemia, also characterized by low-grade inflammation, were recently associated with more aggressive forms of Graves' ophthalmopathy. The association between obesity and autoimmune thyroid disorders may also go in the opposite direction, as treating autoimmune hyper and hypothyroidism can lead to weight gain. In addition, restoration of euthyroidism by L-T4 replacement therapy is more challenging in obese athyreotic patients, as it is difficult to maintain thyrotropin stimulation hormone (TSH) values within the normal range. Intriguingly, pro-inflammatory cytokines decrease in obese patients after bariatric surgery along with TSH levels. Moreover, the risk of thyroid cancer is increased in patients with thyroid autoimmune disorders, and is also related to the degree of obesity and inflammation. Molecular studies have shown a relationship between the low-grade inflammation of obesity and the activity of intracellular multiprotein complexes typical of immune cells (inflammasomes). We will now highlight some clinical implications of inflammasome activation in the relationship between obesity and thyroid disease.

Mediating effect analysis of visceral adiposity index on free triiodothyronine to free thyroxine ratio and non-alcoholic fatty liver disease in euthyroid population

BACKGROUND

The association between free triiodothyronine/free thyroxine (FT3/FT4) and non-alcoholic fatty liver disease (NAFLD) in euthyroid subjects is unclear. In addition, few studies have explored whether VAI mediates the association between FT3/FT4 ratio and NAFLD in the euthyroid population. We aimed to analyze the mediating effect of VAI on the FT3/FT4 ratio and NAFLD risk in the euthyroid population.

METHODS

This cross-sectional study included 7 946 annual health examinees from the Health Examination Center, Hebei General Hospital, from January to December 2020. The basic information and biochemical parameters, as well as calculated FT3/FT4 ratio and VAI were collected. NAFLD was diagnosed according to abdominal ultrasonography. The fibrosis score for NAFLD positive subjects (NFS) was calculated to reflect the extent of liver fibrosis. The risk of NAFLD was analyzed by quartiles of FT3/FT4 ratio (Q1-Q4 quartiles) and VAI (V1-V4 quartiles), respectively. Pearson correlation analysis was performed to investigate the correlation between FT3/FT4 ratio and VAI. Multivariate logistic regression analysis was applied to analyze the effect of FT3/FT4 ratio and VAI on NAFLD and NFS status. Bootstrap was conducted to explore whether VAI mediated the association between FT3/FT4 ratio and NAFLD.

RESULTS

Of the 7 946 participants, 2 810 (35.36%) had NAFLD and 5 136 (64.64%) did not. Pearson correlation analysis indicated that FT3/FT4 ratio was positively associated with VAI (P<0.05). Multivariate logistic regression analysis indicated that compared to the Q1 group, the risk of NAFLD significantly increased in Q3 group [OR=1.255, 95%CI (1.011, 1.559)] and Q4 group [OR=1.553, 95%CI (1.252, 1.926)](P<0.05). Compared to the V1 group, the risk of NAFLD notably increased in V2 group [OR=1.584, 95%CI (1.205, 2.083)], V3 group [OR=2.386, 95%CI (1.778, 3.202)] and V4 group [OR=4.104, 95%CI (2.835, 5.939)] (P<0.01). There was no relevance between FT3/FT4 ratio, VAI and NFS status. Mediating effect analysis showed that FT3/FT4 ratio significantly directly influenced NAFLD prevalence [β=3.7029, 95%CI (2.9583, 4.4474)], and VAI partly mediated the indirect effect of the FT3/FT4 ratio on NAFLD prevalence [β=2.7649, 95%CI (2.2347, 3.3466)], and the mediating effect accounted for 42.75% of the total effects.

CONCLUSION

Both FT3/FT4 ratio and VAI were predictors of NAFLD, and VAI partly mediated the indirect effect of the FT3/FT4 ratio on NAFLD prevalence in the euthyroid population.

New Anthropometric Measurements: Relationship to Thyroid Functions in Euthyroid Obese Subjects

Introduction

Body mass index (BMI) is unable to make a distinction between muscle mass and fat mass. Therefore, new anthropometric measurements, such as a body shape index (ABSI), body round index (BRI), and body adiposity index (BAI), have been formulated in recent years. Many studies have reported a correlation between BMI and thyroid function. In this study, we aimed to investigate the relationship between the above-mentioned new anthropometric measurements and thyroid functions in euthyroid obese subjects.

Methods

We included 675 euthyroid (TSH ≥ 0.4 and < 4.5 mIU/l) individuals from the obesity outpatient clinic, aged between 18 and 65 years old, with BMI ≥ 30. Thyroid-stimulating hormone (TSH), free T4 (fT4) and free T3 (fT3), anthropometric measurements (weight, height, and waist circumference), and bioelectric impedance analyses [percent body fat (PBF) and fat-free mass (FFM)] of individuals were measured and recorded. ABSI, BRI, and BAI were calculated with the data from these measurements. Anthropometric measurements were compared to thyroid function tests.

Results

Eighty percent of the subjects were female. The mean age and BMI were 38 ± 17 years and 38 ± 6 kg/m², respectively. TSH was found to be negatively correlated with ABSI (p = 0.006) and positively correlated with BAI (p < 0.001), but a statistically significant relationship with BRI (p = 0.193) was not determined. Free T4 was not associated with any of the anthropometric measurements.While fT3 was determined to be positively correlated with ABSI (p = 0.008) and negatively correlated with PBF and BAI (p = 0.001, p = 0.002, respectively), no statistically significant relationship with fT3 and BRI was determined.

Conclusion

TSH is positively correlated with measurements of adiposity such as BMI, PBF, BAI while indexes in which abdominal obesity increases, such as waist circumference (WC), waist-hip ratio (WHR), and ABSI, are correlated with fT3 levels.

Leptin-A Potential Bridge between Fat Metabolism and the Brain's Vulnerability to Neuropsychiatric Disorders: A Systematic Review

BACKGROUND

Obesity and being overweight have been described as potential causes of neurological disorders. Leptin, a peptide expressed in fat tissue, importantly participates in energy homeostasis and storage and has recently been identified for its signaling receptors in neuronal circuits of the brain.

AIM

To elucidate whether the endogenous modulation of leptin can be a protection against neuropsychiatric disorders.

METHOD

A systematic review was performed in accordance with the PRISMA-P method, and reports of studies containing data of leptin concentrations in healthy individuals with or without obesity were retrieved from the PubMed database, using the combinations of Mesh terms for "Leptin" and "Metabolism".

RESULTS

Forty-seven randomized and non-randomized controlled trials, dating from 2000 to 2021, were included in the qualitative synthesis.

DISCUSSION AND CONCLUSIONS

Leptin secretion displays a stabilizing pattern that is more sensitive to a negative energy intake imbalance. Leptin levels influence body weight and fat mass as a pro-homeostasis factor. However, long-term exposure to elevated leptin levels may lead to mental/behavioral disorders related to the feeding and reward systems.

Orally Induced Hyperthyroidism Regulates Hypothalamic AMP-Activated Protein Kinase

Besides their direct effects on peripheral metabolic tissues, thyroid hormones (TH) act on the hypothalamus to modulate energy homeostasis. However, since most of the hypothalamic actions of TH have been addressed in studies with direct central administration, the estimation of the relative contribution of the central vs. peripheral effects in physiologic conditions of peripheral release (or administration) of TH remains unclear. In this study we used two different models of peripherally induced hyperthyroidism (i.e., T4 and T3 oral administration) to assess and compare the serum and hypothalamic TH status and relate them to the metabolic effects of the treatment. Peripheral TH treatment affected feeding behavior, overall growth, core body temperature, body composition, brown adipose tissue (BAT) morphology and uncoupling protein 1 (UCP1) levels and metabolic activity, white adipose tissue (WAT) browning and liver metabolism. This resulted in an increased overall uncoupling capacity and a shift of the lipid metabolism from WAT accumulation to BAT fueling. Both peripheral treatment protocols induced significant changes in TH concentrations within the hypothalamus, with T3 eliciting a downregulation of hypothalamic AMP-activated protein kinase (AMPK), supporting the existence of a central action of peripheral TH. Altogether, these data suggest that peripherally administered TH modulate energy balance by various mechanisms; they also provide a unifying vision of the centrally mediated and the direct local metabolic effect of TH in the context of hyperthyroidism.

The Association between the Dietary Inflammatory Index and Thyroid Function in U.S. Adult Males

Thyroid function has a close link with inflammation. However, it is still unknown whether the dietary inflammatory potential is associated with thyroid function. We aimed to assess the relationship among them using the data from the National Health and Nutrition Examination Survey (NHANES). This study was a cross-sectional study, where weighted multivariable linear regression, subgroup analyses, and interaction terms were employed. Thyroid function was assessed by eight indexes, including total and free T4 and T3, Tg, TgAb, TPOAb, and TSH. A total of 2346 male participants aged ≥20 years with an average age of 50.74 ± 17.68 years were enrolled. The mean DII score among participants was −0.46 ± 1.73, ranging from −4.12 to 4.41, and mean total thyroxine (T4) was 7.61 ± 1.51 μg/dL. We found a positive association between DII and total T4 (β = 0.07; p = 0.0044). Using subgroup analysis, this association became stronger in both the iodine-deficient and obese group (iodine-deficient group: β = 0.15, p < 0.0001; obese group: β = 0.14, p < 0.0001). In conclusion, men adhering to a more pro-inflammatory diet appeared to have higher total T4 levels. However, these hormone variations were still within the normal clinical range and more well-designed studies are still needed to validate the causal relationship between DII and thyroid function.

Patterns of Bodyweight Changes in Patients With Hypothyroidism, a Retrospective Study From Basrah, Southern Iraq

Background

Weight gain is one of the most important hypothyroidism-related concerns in patients with hypothyroidism. However, unexpectedly, levothyroxine replacement does not necessarily result in body weight (BWT) reduction among those patients. The study aimed to assess the patterns of BWT changes through time in patients with hypothyroidism.

Method

In a retrospective database study from Faiha Specialized Diabetes, Endocrine, and Metabolism Center, a total of 346 adult patients with hypothyroidism (192 newly diagnosed and 154 known hypothyroidism patients) who had one visit every three months, five visits in one year were included. Of these, 116 new and 69 known hypothyroidism patients had completed nine visits in two years. Each visit involved thyroid-stimulating hormone (TSH) and BWT measurements. Patients with chronic liver or renal disease, diabetes mellitus, thyroid cancer, or other malignancies, pregnancy, and steroid or hormonal therapies were excluded. The patients were further subdivided based on average TSH levels into controlled (TSH ≤ 4.2 μIU/ml) and uncontrolled (TSH > 4.2 μIU/ml). Repeated measures analysis of variance (ANOVA) with a Greenhouse-Geisser correction and post hoc tests using the Bonferroni correction were used to evaluate TSH and BWT changes through the study.

Results

Both in newly diagnosed and known hypothyroidism patients with an average TSH > 4.2 μIU/mL, BWT increased significantly through visits over one and two years. For newly diagnosed patients assessed over one year (F(2.41, 321.60) = 3.28, p = 0.03), the mean BWT increase was 1.4 ± 0.38 kg from 3rd to 12th month visits (p = 0.004). For newly diagnosed patients assessed over two years (F(3.10, 263.89) = 9.08, P < 0.0005), the mean BWT increase was 3.02 ± 0.77 kg from 3rd to 24th month visits (p = 0.007). For patients with known hypothyroidism assessed over one year (F(2.56, 187.47) = 7.11, p = 0.0003), the mean BWT increase was 1.97 ± 0.64 kg at 12th month visit, and over two years (F(2.35, 77.56) = 4.67, P = 0.009), the mean BWT increase was 3.78 ± 1.26 kg at 24th month visit. While in all other patients with an average TSH ≤ 4.2 μIU/mL, the BWT changed non-significantly through the visits for newly diagnosed patients over one year and two years (p = 0.10, 0.34, respectively), and known patients over one year and two years (p = 0.47, 0.34, respectively).

Conclusion

Contrary to what is believed, adequate treatment with levothyroxine does not associate with weight reduction. Instead, either the patient kept on the same weight or continued to gain more weight.

Common Electrolyte and Metabolic Abnormalities Among Thyroid Patients

The prevalence of thyroid diseases is high in the general population and causes serious abnormalities and disorders that can affect the quality of life. Many complications can result from poor or inappropriate management of the disease, leading to serious cardiovascular and metabolic complications. In the present review study, we aim to discuss the effect of thyroid diseases on metabolic and electrolyte abnormalities and the potential correlation with some common disorders. Evidence from previous studies has demonstrated that thyroid dysfunctions hugely affect the metabolism of glucose in the bodies of the affected patients, which can lead to the development of both type 1 and 2 diabetes mellitus (DM). Hyperthyroidism can lead to the development of impaired glucose tolerance and secondary diabetes mellitus. These include an increased glycogenolysis and gluconeogenesis process, increased intestinal absorption of glucose, and secondary ketogenesis and lipolysis, which will subsequently affect the functions of the insulin-secreting cells of the pancreas. Evidence showed that thyroid diseases are associated with the development of obesity and metabolic syndrome, and the management for these modalities should involve prior management of underlying thyroid diseases. Efforts should be made to adequately manage these cases with concomitant approaches to achieve the best clinical outcomes.

Central vs. Peripheral Action of Thyroid Hormone in Adaptive Thermogenesis: A Burning Topic

Thyroid hormones (TH) contribute to the control of adaptive thermogenesis, which is associated with both higher energy expenditure and lower body mass index. While it was clearly established that TH act directly in the target tissues to fulfill its metabolic activities, some studies have rather suggested that TH act in the hypothalamus to control these processes. This paradigm shift has subjected the topic to intense debates. This review aims to recapitulate how TH control adaptive thermogenesis and to what extent the brain is involved in this process. This is of crucial importance for the design of new pharmacological agents that would take advantage of the TH metabolic properties.

Genetics-Based Approach to Identify Novel Genes Regulated by the Aryl Hydrocarbon Receptor in Mouse Liver

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor in the Per-Arnt-Sim superfamily of environmental sensors that is linked to several metabolic diseases, including nonalcoholic fatty liver disease. Much remains unknown regarding the impact of genetic variation in AHR-driven disease, as past studies have focused on a small number of inbred strains. Recently, the presence of a wide range of interindividual variability amongst humans was reported in response to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the prototypical ligand of the AHR. In this study, a panel of 14 diverse mouse strains was exposed to TCDD for 10 days to characterize the AHR-mediated response across genetic backgrounds. Responses to TCDD are heavily dependent on genetic background. Although mice carry 1 of 4 Ahr alleles known to impact the affinity to AHR-ligands, we observed significant intra-allelic variability suggesting the presence of novel genetic modifiers of AHR signaling. A regression-based approach was used to scan for genes regulated by the AHR and/or associated with TCDD-induced phenotypes. The approach identified 7 genes, 2 of which are novel, that are likely regulated by the AHR based on association with hepatic TCDD burden (p ≤ .05). Finally, we identified 1 gene, Dio1, which was associated with change in percent body fat across the diverse set of strains (p ≤ .05). Overall, the results in this study exemplify the power of genetics-based approaches in identifying novel genes that are putatively regulated by the AHR.

Evidence-based weight loss interventions: Individualized treatment options to maximize patient outcomes

Against the backdrop of obesity as a major public health problem, we examined three questions: How much weight loss is needed to benefit patients with obesity? How well do current therapies do in producing weight loss? What strategies can be used to improve patient outcomes using evidence-based studies. This paper reviews literature on the outcomes of lifestyle, diet, medications and surgical treatments for obesity using literature searches for obesity treatments. Current treatments, including lifestyle, diet and exercise, produce a weight loss of 5% to 7% on average. Despite continued attempts to identify superior dietary approaches, most careful comparisons find that low carbohydrate diets are not significantly better than low fat diets for weight loss. The four medications currently approved by the US Food and Drug Administration for long-term management of obesity are not as effective as surgery, adding about 5% on average to lifestyle approaches to weight loss. Two new medications that are under investigation, semaglutide and tirzepatide, significantly improve on this. For all treatments for weight loss, including lifestyle, medications and surgery, there is enormous variability in the amount of weight lost. Examination of this literature has yielded evidence supporting baseline and process predictors, but the effect sizes associated with these predictors are small and there are no prospective studies showing that a personalized approach based on genotype or phenotype will yield uniform success. Because obesity is a chronic disease it requires a 'continuous treatment model' across the lifespan.

The possible role of the seaweed Ulva fasciata on ameliorating hyperthyroidism-associated heart inflammations in a rat model

Cardiovascular diseases are key complications primarily associated with hyperthyroidism disorders. The present study sought to ameliorate hyperthyroidism-mediated cardiovascular inflammations and related oxidative stress paradigms in experimental rats using the broadly distributed green seaweed Ulva fasciata. Forty-eight adult male albino rats were recruited and randomly classified into six groups. Hyperthyroidism was stimulated using L-thyroxine sodium at a dose of 100 μg/kg i.p. for 3 weeks daily. Further, 200 mg/kg b.wt. concentration of the U. fasciata methanolic (U. fasciata-MeOH) extract was the recommended dose and administrated orally to the hyperthyroid rats. The standard commercial drug "propranolol hydrochloride" was also tested at a dose of 10 mg/kg i.p. to compare the findings obtained from the seaweed extract. A combined treatment with the U. fasciata-MeOH extract and propranolol hydrochloride was also assessed. Our results implied that the treatment of hyperthyroid rats with the U. fasciata-MeOH extract significantly reduced serum levels of the thyroid hormones T3 and T4, proinflammatory cytokines (TNF-α, MPO, and CRP), triglycerides and total cholesterol, as well as the cardiac biomarkers CK-MB, LDH, and troponin to thresholds close to those of the standard drug. In addition, levels of high-density lipoprotein cholesterol (HDL-C) and interleukin 10 (IL-10) were significantly upregulated. Hyperthyroid rats only treated with propranolol hydrochloride, or with a combination of the drug and the seaweed extract, conferred the same observations. Histopathological architecture boosted our interesting findings where the myocardium tissues in hyperthyroid rats, administrated the U. fasciata-MeOH extract or/and propranolol hydrochloride, exhibited more or less a normal structure as the control, reflecting the potential cardiovascular recovery exerted by this seaweed extract. In vitro DPPH, ABTS, and FRAP antioxidant assays of the U. fasciata-MeOH extract showed an outstanding ROS-scavenging potential. HPLC analysis of the U. fasciata-MeOH extract unraveled an inestimable valuable array of phenolics (mainly p-coumaric, gallic, ferulic, chlorogenic, and syringic acids) and flavonoids (hesperidin, kaempferol, catechin, quercetin, and rutin). Conclusively, the seaweed U. fasciata is a profitable source of antioxidant polyphenolics characterized by having a pharmaceutical potential against hyperthyroidism-linked cardiovascular inflammations and oxidative stress patterns due to their substantial free radical quenching properties, and also via regulating the signalling pathways of the proinflammatory, lipid profile, and cardiac biomarkers.

Factors affecting weight loss variability in obesity

Current obesity treatment strategies include diet, exercise, bariatric surgery, and a limited but growing repertoire of medications. Individual weight loss in response to each of these strategies is highly variable. Here we review research into factors potentially contributing to inter-individual variability in response to treatments for obesity, with a focus on studies in humans. Well-recognized factors associated with weight loss capacity include diet adherence, physical activity, sex, age, and specific medications. However, following control for each of these, differences in weight loss appear to persist in response to behavioral, pharmacological and surgical interventions. Adaptation to energy deficit involves complex feedback mechanisms, and inter-individual differences likely to arise from a host of poorly defined genetic factors, as well as differential responses in neurohormonal mechanisms (including gastrointestinal peptides), metabolic efficiency and capacity of tissues, non-exercise activity thermogenesis, thermogenic response to food, and in gut microbiome. A better understanding of the factors involved in inter-individual variability in response to therapies will guide more personalized approaches to the treatment of obesity.

The role of thyroid hormone in metabolism and metabolic syndrome

Metabolic syndrome (MetS) and thyroid dysfunction are common in clinical practice. The objectives of this review are to discuss some proposed mechanisms by which thyroid dysfunctions may lead to MetS, to describe the bidirectional relationship between thyroid hormones (THs) and adiposity and finally, to resume a list of recent studies in humans that evaluated possible associations between thyroid hormone status and MetS or its clinical components. Not solely THs, but also its metabolites regulate metabolic rate, influencing adiposity. The mechanisms enrolled are related to its direct effect on adenosine triphosphate (ATP) utilization, uncoupling synthesis of ATP, mitochondrial biogenesis, and its inotropic and chronotropic effects. THs also act controlling core body temperature, appetite, and sympathetic activity. In a bidirectional way, thyroid function is affected by adiposity. Leptin is one of the hallmarks, but the pro-inflammatory cytokines and also insulin resistance impact thyroid function and perhaps its structure. MetS development and weight gain have been positively associated with thyroid-stimulating hormone (TSH) in several studies. Adverse glucose metabolism may be related to hyperthyroidism, but also to reduction of thyroid function or higher serum TSH, as do abnormal serum triglyceride levels. Hypo- and hyperthyroidism have been related to higher blood pressure (BP), that may be consequence of genomic or nongenomic action of THs on the vasculature and in the heart. In summary, the interaction between THs and components of MetS is complex and not fully understood. More longitudinal studies controlling each of all confounding variables that interact with endpoints or exposure factors are still necessary.

Impact of the Co-Administration of N-3 Fatty Acids and Olive Oil Components in Preclinical Nonalcoholic Fatty Liver Disease Models: A Mechanistic View

Nonalcoholic fatty liver disease (NAFLD) is present in approximately 25% of the population worldwide. It is characterized by the accumulation of triacylglycerol in the liver, which can progress to steatohepatitis with different degrees of fibrosis, stages that lack approved pharmacological therapies and represent an indication for liver transplantation with consistently increasing frequency. In view that hepatic steatosis is a reversible condition, effective strategies preventing disease progression were addressed using combinations of natural products in the preclinical high-fat diet (HFD) protocol (60% of fat for 12 weeks). Among them, eicosapentaenoic acid (C20:5n-3, EPA) and docosahexaenoic acid (C22:5n-3, DHA), DHA and extra virgin olive oil (EVOO), or EPA plus hydroxytyrosol (HT) attained 66% to 83% diminution in HFD-induced steatosis, with the concomitant inhibition of the proinflammatory state associated with steatosis. These supplementations trigger different molecular mechanisms that modify antioxidant, antisteatotic, and anti-inflammatory responses, and in the case of DHA and HT co-administration, prevent NAFLD. It is concluded that future studies in NAFLD patients using combined supplementations such as DHA plus HT are warranted to prevent liver steatosis, thus avoiding its progression into more unmanageable stages of the disease.

Thyroid Function and Nutrient Status in the Athlete

Thyroid disease is common in the general population, especially in women, and also may be prevalent among athletes. Autoimmune disorders are the most common cause of thyroid disorders in countries with iodine-fortification programs; however, thyroid dysfunction can be brought on by nutritional factors, including insufficient energy intake and iodine, selenium, iron, and vitamin D deficiency. Additionally, strenuous exercise may be associated with transient alterations in thyroid hormones. While the development of thyroid related disorders has the potential to impact health and peak performance, typical clinical manifestations are highly variable, lack specificity, and are frequently confused with other health problems. The assessment process should focus on anthropometric changes, biochemical tests (thyroid panel), personal and family history, examination for appropriate signs and symptoms, and diet and environmental assessment that includes adequacy of energy, iodine, iron, selenium, and vitamin D intake/status along with excess stress and exposure to environmental contaminants and dietary goitrogens.

Central Resistance to Thyroid Hormones in Morbidly Obese Subjects Is Reversed after Bariatric Surgery-Induced Weight Loss

Endocrine abnormalities are common in obesity, including altered thyroid function. The altered thyroid function of obesity may be due to a mild acquired resistance to the thyroid hormone. The aim of this study was to investigate the effect of weight loss after bariatric surgery (BS) on resistance to thyroid hormones in patients with extreme obesity compared with a control group. We performed an observational study evaluating patients with extreme obesity who underwent BS. We included 106 patients (83 women) and 38 controls (24 women). The primary endpoint was the thyrotroph thyroxine resistance index (TT4RI) and thyroid stimulating hormone (TSH) index (TSHRI). The parameters were studied before and after surgery. TSHRI and TT4RI were higher in the obese patients than in the control group. TT4RI and TSHI decreased significantly over time after surgery, with this decrease being associated with the excessive body mass index (BMI) loss and C-reactive protein (CRP). In extreme obesity, BS promotes a significant decrease in the increased TT4RI and TSHI. This decrease of TT4RI and TSHI is progressive over time after BS and significantly associated with excess BMI lost and CRP. Extreme obesity is characterized by a mild reversible central resistance to thyroid hormones.

Maternal high-protein diet modulates hepatic growth axis in weaning piglets by reprogramming the IGFBP-3 gene

PURPOSE

The aim of this study was to investigate the effects of maternal high dietary protein intake on the hepatic growth axis in offspring.

METHODS

Fourteen primiparous purebred Meishan sows were fed either a standard-protein (SP, n = 7) diet or a high-protein (HP, 150% of SP, n = 7) diet during pregnancy. Offspring (one male and one female per group, n = 14) on day 70 of the embryonic stage and on days 1, 35 and 180 after birth were selected, weighed and killed. Serum samples were analyzed for Tch, insulin and insulin-like growth factor-binding protein 3 (IGFBP-3) levels. Liver samples were analyzed for IGFBP-3 and IGF-I mRNA expression by qRT-PCR and for IGFBP-3, IGF1R and growth hormone receptor (GHR) protein expression by Western blotting. The underlying mechanism of IGFBP-3 regulation was determined by methylated DNA immunoprecipitation (MeDIP) and chromatin immunoprecipitation (ChIP).

RESULTS

High-protein exposure resulted in significantly higher body and liver weights of piglets, and it increased their serum T3 and T4 levels at birth and/or at weaning. Furthermore, the IGFBP-3 protein content in the liver and serum was significantly reduced in the HP-exposed weaning piglets, whereas at the transcriptional level IGFBP-3 mRNA expression was downregulated in the livers of HP group piglets. Finally, DNA hypermethylation and higher enrichment of the histone repressive marks H3K27me3 and H3K9me3 were observed.

CONCLUSIONS

Taken together, these results suggest that a maternal high-protein diet during gestation epigenetically reprograms IGFBP-3 gene expression to modulate the hepatic growth axis in weaning piglets.

Lessons Learned from the POUNDS Lost Study: Genetic, Metabolic, and Behavioral Factors Affecting Changes in Body Weight, Body Composition, and Cardiometabolic Risk

PURPOSE OF REVIEW

This paper reviews the genetic and non-genetic factors that provided predictions of, or were associated with, weight loss and other metabolic changes in the POUNDS Lost clinical trial of weight loss. This trial randomized 811 individuals who were overweight or obese to one of four diets that contained either 15% or 25% protein and 20% or 40% fat in a 2 × 2 factorial design. A standard behavioral weight loss program was available for all participants who were followed for 2 years with an 80% completion rate.

RECENT FINDINGS

Nineteen genes and five genetic risk scores were used along with demographic, behavioral, endocrine, and metabolic measurements. Genetic variations in most of the genes were associated with weight loss, but this association often varied with the dietary assignment. A number of demographic and behavioral factors, including attendance at behavioral sessions and food cravings were predictive of weight changes. A high baseline level of free triiodothyronine or free thyroxine predicted the magnitude of weight loss. Several perfluoroakyl compounds predicted more rapid weight regain. Genetic evidence from POUNDS Lost provides guidance toward selection of a personalized weight loss diet and improvement in metabolic profile. There is still room for additional research into the predictors of weight loss.

Mifepristone Increases Thyroid Hormone Requirements in Patients With Central Hypothyroidism: A Multicenter Study

Purpose

Mifepristone is a glucocorticoid and progesterone receptor blocker that can be used for patients with hyperglycemia and Cushing syndrome in whom surgery failed to achieve remission or who were ineligible for surgery. We report a case series of patients with Cushing disease (CD) and central hypothyroidism that presented with increased levothyroxine requirements during mifepristone therapy.

Methods

Retrospective longitudinal case series of patients with CD and central hypothyroidism treated with mifepristone in a retrospective database at four pituitary centers in the United States.

Results

Five patients with CD were found, all women, median age 50 (interquartile range 47 to 64.5). They received mifepristone because no adequate response or intolerance to other drugs was observed. Mifepristone initiation was associated with a decrease in free thyroxine levels, mandating a dose increase of a median 1.83 (1.71 to 3.5) times the initial dose of levothyroxine to achieve normal levels. Weight loss was seen in four of five patients, ranging from 3.2 to 42.6 kg in up to 54 months of follow-up.

Conclusions

Although the mechanism behind the decrease in thyroid hormone level is unknown, intestinal malabsorption, decreased residual thyroid function and increased inactivation of T4 via deiodinases are all potential causes. Whereas therapies for hypercortisolism aim to decrease features of hypercortisolemia such as weight gain and depression, hypothyroidism can hamper these goals. This case series raises awareness on the importance of assessment of thyroid status in patients receiving mifepristone to optimize clinical outcomes.

Effect of Weight Loss after Bariatric Surgery on Thyroid-Stimulating Hormone Levels in Euthyroid Patients with Morbid Obesity

Obesity is associated with several endocrine abnormalities, including thyroid dysfunction. The objective of this study was to investigate the effect of weight loss after bariatric surgery on thyroid-stimulating hormone (TSH) levels in euthyroid patients with morbid obesity. We performed an observational study, evaluating patients with morbid obesity submitted to bariatric surgery. We included 129 patients (92 women) and 31 controls (21 women). Clinical, anthropometric, biochemical, and hormonal parameters were evaluated. The primary endpoint was circulating TSH (µU/mL). Fasting TSH levels were higher in the obese group (3.3 ± 0.2) than in the control group (2.1 ± 0.2). The mean excessive body mass index (BMI) loss (EBMIL) 12 months after bariatric surgery was 72.7 ± 2.1%. TSH levels significantly decreased in the obese patients after surgery; 3.3 ± 0.2 vs. 2.1 ± 0.2 before and 12 months after surgery, respectively. Free thyroxine (T4) (ng/dL) levels significantly decreased in the obese patients after surgery; 1.47 ± 0.02 vs. 1.12 ± 0.02 before and 12 months after surgery, respectively. TSH decreased significantly over time, and the decrement was associated with the EBMIL. In euthyroid patients with morbid obesity, weight loss induced by bariatric surgery promotes a significant decline of the increased TSH levels. This decrement of TSH is progressive over time after surgery and significantly associated with excess BMI loss.

Combined docosahexaenoic acid and thyroid hormone supplementation as a protocol supporting energy supply to precondition and afford protection against metabolic stress situations

Liver preconditioning (PC) refers to the development of an enhanced tolerance to injuring stimuli. For example, the protection from ischemia-reperfusion (IR) in the liver that is obtained by previous maneuvers triggering beneficial molecular and functional changes. Recently, we have assessed the PC effects of thyroid hormone (T_3; single dose of 0.1 mg/kg) and n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs; daily doses of 450 mg/kg for 7 days) that abrogate IR injury to the liver. This feature is also achieved by a combined T₃ and the n-3 LCPUFA docosahexaenoic acid (DHA) using a reduced period of supplementation of the FA (daily doses of 300 mg/kg for 3 days) and half of the T₃ dosage (0.05 mg/kg). T₃ -dependent protective mechanisms include (i) the reactive oxygen species (ROS)-dependent activation of transcription factors nuclear factor-κB (NF-κB), AP-1, signal transducer and activator of transcription 3, and nuclear factor erythroid-2-related factor 2 (Nrf2) upregulating the expression of protective proteins. (ii) ROS-induced endoplasmic reticulum stress affording proper protein folding. (iii) The autophagy response to produce FAs for oxidation and ATP supply and amino acids for protein synthesis. (iv) Downregulation of inflammasome nucleotide-bonding oligomerization domain leucine-rich repeat containing family pyrin containing 3 and interleukin-1β expression to prevent inflammation. N-3 LCPUFAs induce antioxidant responses due to Nrf2 upregulation, with inflammation resolution being related to production of oxidation products and NF-κB downregulation. Energy supply to achieve liver PC is met by the combined DHA plus T₃ protocol through upregulation of AMPK coupled to peroxisome proliferator-activated receptor-γ coactivator 1α signaling. In conclusion, DHA plus T₃ coadministration favors hepatic bioenergetics and lipid homeostasis that is of crucial importance in acute and clinical conditions such as IR, which may be extended to long-term or chronic situations including steatosis in obesity and diabetes. © 2019 IUBMB Life, 71(9):1211-1220, 2019.

Long-term pharmacotherapy of obesity in patients that have undergone bariatric surgery: pharmacological prevention and management of body weight regain

INTRODUCTION

The obesity epidemic continues to grow. Bariatric surgery is part of the arsenal to treat the disease. Surgery results in an effective option for patients with severe obesity but also when obesity is associated with significant comorbidities. Weight regain is frequent after bariatric surgery. Consequently, the addition of anti-obesity drugs to prevent and manage weight regain are commonly recommended even when the quality of the evidence supporting this recommendation is relatively weak. cfsda65

AREAS COVERED

The aim of this review is to summarize the available evidence concerning long-term pharmacotherapy of obesity in patients that have undergone bariatric surgery with a focus on pharmacological prevention and management of weight regain. The etiology and epidemiology of weight regain are summarized, as well as the available information about the benefits and risks of long-term pharmacotherapy in the prevention and management of recidivism.

EXPERT OPINION

The available information, mainly obtained from observational studies and small trials, is encouraging but calls for a prudent approach in the selection of appropriate agents for each individual patient and a careful follow-up to detect adverse reactions or drug interactions. Results from well-designed trials are upcoming. In the meantime, a cautious, individualized approach is advisable.

Docosahexaenoic acid-thyroid hormone combined protocol as a novel approach to metabolic stress disorders: Relation to mitochondrial adaptation via liver PGC-1α and sirtuin1 activation

Docosahexaenoic acid (DHA) and 3,3',5-triiodothyronine (T₃ ) combined protocol affords protection against liver injury via AMPK signaling supporting energy requirements. The aim of this work was to test the hypothesis that a DHA + T₃ accomplish mitochondrial adaptation through downstream upregulation of PPAR-γ coactivator 1α (PGC-1α). Male Sprague-Dawley rats were given daily oral doses of 300 mg DHA/kg or saline (controls) for three consecutive days, followed by 0.05 mg T₃ /kg (or hormone vehicle) ip at the fourth day, or single dose of 0.1 mg T₃ /kg alone. Liver mRNA levels were assayed by qPCR, NAD⁺ /NADH ratios, hepatic proteins, histone 3 acetylation and serum T₃ and β-hydroxybutyrate levels were determined by specific ELISA kits. Combined DHA + T₃ protocol led to increased liver AMPK, PGC-1α, NRF-2, COX-IV, and β-ATP synthase mRNAs, with concomitant higher protein levels of COX-IV and NRF-2, 369% enhancement in the NAD⁺ /NADH ratio, 47% decrease in histone 3 acetylation and 162% increase in serum levels of β-hydroxybutyrate over control values. These changes were reproduced by the higher dose of T₃ without major alterations by DHA or T₃ alone. In conclusion, liver mitochondrial adaptation by DHA + T₃ is associated with PGC-1α upregulation involving enhanced transcription of the coactivator, which may be contributed by PGC-1α deacetylation and phosphorylation by SIRT1 and AMPK activation, respectively. This contention is supported by NRF-2-dependent enhancement in COX-1 and β-ATP synthase induction with higher fatty acid oxidation resulting in a significant ketogenic response, which may represent a suitable strategy for hepatic steatosis with future clinical applications. © 2018 BioFactors, 45(2):271-278, 2019.

Decreased Leptin Is Associated with Alterations in Thyroid-Stimulating Hormone Levels after Roux-en-Y Gastric Bypass Surgery in Obese Euthyroid Patients with Type 2 Diabetes

BACKGROUND

Leptin has been shown to stimulate the hypothalamus-pituitary-thyroid (HPT) axis in vivo and vitro. Its role in thyroid axis regulation after weight loss induced by bariatric surgery is still unknown. The aim of this study was to evaluate the influence of leptin on weight loss and thyroid function variation induced by Roux-en-Y gastric bypass (RYGB) surgery in euthyroid individuals with obesity and type 2 diabetes mellitus (T2DM).

METHODS

65 Chinese individuals with obesity and T2DM who underwent RYGB, and 27 healthy volunteers were enrolled in this retrospective study. Participants were evaluated for changes in anthropometric parameters, metabolic indexes, thyroid function, and leptin levels before and 12 months after surgery.

RESULTS

After RYGB, all of these patients experienced significant weight reduction and improved glucose control. Metabolic parameters were significantly ameliorated after surgery compared with baseline. Thyroid hormones including free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) declined in parallel. Median (IQR) plasma leptin levels decreased from 33.7 ng/mL (17.9-63.1) to 10.3 ng/mL (4.0-18.5). Pearson correlation analysis showed that TSH was significantly positively correlated with body mass index, C-reactive protein (CRP), and leptin. Multiple stepwise linear regression indicated that leptin and CRP were independent factors affecting TSH. The β coefficients were 0.38 (p = 0.001) and 0.32 (p = 0.004), respectively. There was a significant positive correlation between ΔTSH and Δleptin (r = 0.33, p = 0.01).

CONCLUSION

Decreased or normalized TSH levels after weight loss induced by RYGB might be mediated by the decline in leptin. There could be cross talk between adipose tissue and the HPT axis.